/*
 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/client/HttpClient.java $
 * $Revision: 676020 $
 * $Date: 2008-07-11 09:38:49 -0700 (Fri, 11 Jul 2008) $
 *
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.client;

import java.io.IOException;

import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.conn.ClientConnectionManager;
import org.apache.http.params.HttpParams;
import org.apache.http.protocol.HttpContext;

/**
 * Interface for an HTTP client. HTTP clients encapsulate a smorgasbord of
 * objects required to execute HTTP requests while handling cookies,
 * authentication, connection management, and other features. Thread safety of
 * HTTP clients depends on the implementation and configuration of the specific
 * client.
 * 
 * @author <a href="mailto:rolandw at apache.org">Roland Weber</a>
 * 
 * 
 *         <!-- empty lines to avoid svn diff problems -->
 * @version $Revision: 676020 $
 * 
 * @since 4.0
 */
public interface HttpClient {

    /**
     * Obtains the parameters for this client. These parameters will become
     * defaults for all requests being executed with this client, and for the
     * parameters of dependent objects in this client.
     * 
     * @return the default parameters
     */
    HttpParams getParams();

    /**
     * Obtains the connection manager used by this client.
     * 
     * @return the connection manager
     */
    ClientConnectionManager getConnectionManager();

    /**
     * Executes a request using the default context.
     * 
     * @param request
     *            the request to execute
     * 
     * @return the response to the request. This is always a final response,
     *         never an intermediate response with an 1xx status code. Whether
     *         redirects or authentication challenges will be returned or
     *         handled automatically depends on the implementation and
     *         configuration of this client.
     * @throws IOException
     *             in case of a problem or the connection was aborted
     * @throws ClientProtocolException
     *             in case of an http protocol error
     */
    HttpResponse execute(HttpUriRequest request) throws IOException,
            ClientProtocolException;

    /**
     * Executes a request using the given context. The route to the target will
     * be determined by the HTTP client.
     * 
     * @param request
     *            the request to execute
     * @param context
     *            the context to use for the execution, or <code>null</code> to
     *            use the default context
     * 
     * @return the response to the request. This is always a final response,
     *         never an intermediate response with an 1xx status code. Whether
     *         redirects or authentication challenges will be returned or
     *         handled automatically depends on the implementation and
     *         configuration of this client.
     * @throws IOException
     *             in case of a problem or the connection was aborted
     * @throws ClientProtocolException
     *             in case of an http protocol error
     */
    HttpResponse execute(HttpUriRequest request, HttpContext context)
            throws IOException, ClientProtocolException;

    /**
     * Executes a request to the target using the default context.
     * 
     * @param target
     *            the target host for the request. Implementations may accept
     *            <code>null</code> if they can still determine a route, for
     *            example to a default target or by inspecting the request.
     * @param request
     *            the request to execute
     * 
     * @return the response to the request. This is always a final response,
     *         never an intermediate response with an 1xx status code. Whether
     *         redirects or authentication challenges will be returned or
     *         handled automatically depends on the implementation and
     *         configuration of this client.
     * @throws IOException
     *             in case of a problem or the connection was aborted
     * @throws ClientProtocolException
     *             in case of an http protocol error
     */
    HttpResponse execute(HttpHost target, HttpRequest request)
            throws IOException, ClientProtocolException;

    /**
     * Executes a request to the target using the given context.
     * 
     * @param target
     *            the target host for the request. Implementations may accept
     *            <code>null</code> if they can still determine a route, for
     *            example to a default target or by inspecting the request.
     * @param request
     *            the request to execute
     * @param context
     *            the context to use for the execution, or <code>null</code> to
     *            use the default context
     * 
     * @return the response to the request. This is always a final response,
     *         never an intermediate response with an 1xx status code. Whether
     *         redirects or authentication challenges will be returned or
     *         handled automatically depends on the implementation and
     *         configuration of this client.
     * @throws IOException
     *             in case of a problem or the connection was aborted
     * @throws ClientProtocolException
     *             in case of an http protocol error
     */
    HttpResponse execute(HttpHost target, HttpRequest request,
            HttpContext context) throws IOException, ClientProtocolException;

    /**
     * Executes a request using the default context and processes the response
     * using the given response handler.
     * 
     * @param request
     *            the request to execute
     * @param responseHandler
     *            the response handler
     * 
     * @return the response object as generated by the response handler.
     * @throws IOException
     *             in case of a problem or the connection was aborted
     * @throws ClientProtocolException
     *             in case of an http protocol error
     */
    <T> T execute(HttpUriRequest request,
            ResponseHandler<? extends T> responseHandler) throws IOException,
            ClientProtocolException;

    /**
     * Executes a request using the given context and processes the response
     * using the given response handler.
     * 
     * @param request
     *            the request to execute
     * @param responseHandler
     *            the response handler
     * 
     * @return the response object as generated by the response handler.
     * @throws IOException
     *             in case of a problem or the connection was aborted
     * @throws ClientProtocolException
     *             in case of an http protocol error
     */
    <T> T execute(HttpUriRequest request,
            ResponseHandler<? extends T> responseHandler, HttpContext context)
            throws IOException, ClientProtocolException;

    /**
     * Executes a request to the target using the default context and processes
     * the response using the given response handler.
     * 
     * @param target
     *            the target host for the request. Implementations may accept
     *            <code>null</code> if they can still determine a route, for
     *            example to a default target or by inspecting the request.
     * @param request
     *            the request to execute
     * @param responseHandler
     *            the response handler
     * 
     * @return the response object as generated by the response handler.
     * @throws IOException
     *             in case of a problem or the connection was aborted
     * @throws ClientProtocolException
     *             in case of an http protocol error
     */
    <T> T execute(HttpHost target, HttpRequest request,
            ResponseHandler<? extends T> responseHandler) throws IOException,
            ClientProtocolException;

    /**
     * Executes a request to the target using the given context and processes
     * the response using the given response handler.
     * 
     * @param target
     *            the target host for the request. Implementations may accept
     *            <code>null</code> if they can still determine a route, for
     *            example to a default target or by inspecting the request.
     * @param request
     *            the request to execute
     * @param responseHandler
     *            the response handler
     * @param context
     *            the context to use for the execution, or <code>null</code> to
     *            use the default context
     * 
     * @return the response object as generated by the response handler.
     * @throws IOException
     *             in case of a problem or the connection was aborted
     * @throws ClientProtocolException
     *             in case of an http protocol error
     */
    <T> T execute(HttpHost target, HttpRequest request,
            ResponseHandler<? extends T> responseHandler, HttpContext context)
            throws IOException, ClientProtocolException;

} // interface HttpClient
